Effect of chemical structure and composition of the resin phase on mechanical strength and vinyl conversion of amorphous calcium phosphate-based composites

The mechanical properties of recently developed bioactive, antidemineralizing/remineralizing, amorphous calcium phosphate (ACP)-based composites need improvement. The objective of this study was to elucidate the effect of structure and composition of resins on the biaxial flexure strength (BFS) and the degree of conversion (DC) of composites attained after photo-polymerization. Two series of 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]propane (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA)/X (X being a neutral or acidic comonomer) ternary resins were prepared and mixed with a mass fraction of 40% of zirconia-hybridized ACP. Both unfilled copolymers and their composites were evaluated for BFS (dry and wet specimens after 2 weeks of immersion in buffered saline) and for DC (after 24 h at 23 degrees C). It was found that for the neutral X monomers, no correlation existed between the hydrophobic/hydrophilic character of the X monomer and the BFS values of the immersed composites. A flexible monomethacrylate yielded copolymers and composites with the highest DC. For the resins utilizing the acidic comonomers, methacrylic acid and mono-4-(methacryloyloxy) ethyltrimellitate (4MET), dry composites with improved BFS values were obtained. 4MET composites exhibited the least loss of strength of all the ternary resin ACP materials. The effect of acidic X on DC was most pronounced for maleic acid copolymers.     

Prenatal diagnosis in Treacher Collins syndrome using combined linkage analysis and ultrasound imaging.

Treacher Collins syndrome is an autosomal dominant disorder of facial development, the features of which include conductive hearing loss and cleft palate. In the current investigation, linkage analysis has been used to make first trimester diagnostic predictions in a pregnancy at high risk of producing an affected child. The results of this analysis predicted that the child would be affected. As predictions of the severity of the disease were not possible, the pregnancy was also assessed by ultrasound imaging. This confirmed the affected diagnosis and predicted that the child would be severely affected.     

Evidence for platelet-activating factor as a late-phase mediator of chronic pancreatitis in the rat.

The role of platelet-activating factor (PAF) as a mediator of pancreatic inflammation was examined in the rat pancreatic duct ligation model of obstructive pancreatitis. Pancreatic generation of PAF, as measured by bioassay (ie, platelet [3H]serotonin secretion), was determined at various times after induction of inflammation. Tissue levels of PAF in the normal pancreas averaged 600 +/- 49 pg/g, but PAF was not detectable during the initial 24 hours of pancreatitis, a time when the inflammatory reaction would be considered acute, that is, during the period of maximal serum amylase release and the development of interstitial edema. However a substantial increase in pancreatic PAF levels (12 times control levels) was observed 7 to 14 days after duct ligation during the late-phase response interval similar to the situation characteristic of chronic pancreatitis in which parenchymal atrophy, fibrosis, and pancreatic insufficiency evolve. One week after duct ligation when PAF levels peaked, an evaluation was made of the effects of PAF antagonists (BN52021 and WEB2170) on pancreatic lesions using Evan's blue extravasation, pancreatic myeloperoxidase (MPO) activity, and acid phosphatase activity in peritoneal lavage fluid. BN52021 or WEB2170 treatment was shown to reduce pancreatic damage and inflammation significantly. Long-term in vivo administration of exogenous PAF (20 micrograms/kg/hr for 7 days) exhibited a reduction of [3H]thymidine uptake into and amylase release from pancreatic acini in vitro. Our observations 1) that pancreatic PAF levels increased significantly during the chronic phase of obstructive pancreatitis induced by duct ligation; 2) that inhibition of the action of PAF, through specific receptor antagonism, caused an attenuation of pancreatic lesions; and 3) that chronic administration of PAF resulted in decreased pancreatic regeneration and exocrine function are consistent with a pivotal role for PAF as a late-phase inflammatory mediator in chronic pancreatitis in rats.     

Regulation of CCR5 expression and MIP-1alpha production in CD4+ T cells from patients with rheumatoid arthritis

Production of CCR5 expression and MIP-1alpha, a ligand of CCR5, by CD4+ T cells from patients with rheumatoid arthritis (RA) were studied. We analysed further the influence of IL-15 stimulation, CD40/CD40 ligand (CD40L) interaction and CCR5 promotor polymorphism. One hundred and fifty-five RA patients and another 155 age- and sex-matched healthy individuals were enrolled. Peripheral CD4+ and double negative (DN) T cells from patients had lower portions of CCR5, whereas synovial CD4+ and DN T cells showed a much higher CCR5 expression. IL-15 significantly up-regulated the expression of CCR5 on purified CD4+ T cells. CD40L expression on synovial CD4+ T cells was increased greatly in CCR5+ portions by IL-15. MIP-1alpha production by synovial CD4+ T cells was also enhanced by IL-15. Co-culture of CD40 expressing synovial fibroblasts with IL-15-activated synovial CD4+ T cells significantly increased MIP-1alpha production. Expression of CCR5 on patients' CD4+ T cells was not influenced by the promotor polymorphism of CCR5 gene. Taken together, these data suggest CCR5+CD4+ T cells infiltrate the inflamed synovium and IL-15 up-regulates CCR5 and CD40L expression further and enhance MIP-1alpha production in synovial CD4+ T cells. Production of MIP-1alpha by synovial fibroblasts is significantly increased by engagement of CD40 with CD40L. Synovial microenvironment plays a potential role in regulation of CCR5+CD4+ T cells in rheumatoid joints.     

Human papillomavirus typing with a polymerase chain reaction-based genotyping array compared with type-specific PCR

BACKGROUND: Type-specific persistence of human papillomavirus (HPV) infection can cause invasive cervical cancer. OBJECTIVES: To evaluate the efficacy of HPV detection and typing with a general polymerase chain reaction (PCR)-based genotyping array and to compare it with a type-specific PCR assay. STUDY DESIGN: Four hundred and thirty-three cervical samples were tested with a modified MY11/GP6+ PCR-based reverse-blot assay (EasyChip HPV Blot; King Car, Taiwan [hereafter HPV Blot]) and with 20 genotypes of L1-type-specific PCR (HPV-6, -11, -16, -18, -31, -33, -35, -39, -45, -51, -52, -53, -56, -58, -59, -62, -66, -68, -70, and -71 [CP8061]). RESULTS: The concordance of the two tests in determining HPV positivity was 96.8% (419/433), with a Cohen's kappa=0.93 (95% CI: 0.90-0.97) and McNemar's test of P=1.0, which indicates excellent agreement. The overall concordance of the two tests in the identification of type-specific HPV was 91.0% (394/433). Sensitivity (90-100%), specificity (99.2-100%), and accuracy (98.6-100%) rates of HPV Blot against the gold standard were satisfactory for HPV-16, -18, -58, -33, -52, -39, -45, -31, -51, -70 while HPV-71 (63.6%) had suboptimal sensitivity. Though the kappa values between the two tests for many individual genotypes could not be reliably calculated because of low positivity, the kappa values for HPV-16, -52, and -58 were excellent (0.93, 0.96, and 0.95, respectively). CONCLUSION: The modified MY11/GP6+ PCR-based HPV Blot assay is accurate and sensitive for detection and genotyping of HPV in cervical swab samples.     

Direct and indirect role of Toll-like receptors in T cell mediated immunity

Toll-like receptors (TLR) are pathogen-associated molecular patterns (PAMPs) recognition receptors that playan important role in protective immunity against infection and inflammation.They act as central integrators ofa wide variety of signals,responding to diverse agonists of microbial products.Stimulation of Toll-like receptorsby microbial products leads to signaling pathways that activate not only innate,but also adaptive immunity byAPC dependent or independent mechanisms.Recent evidence revealed that TLR signals played a determiningrole in the skewing of na(?)ve T cells towards either Th1 or Th2 responses.Activation of Toll-like receptors alsodirectly or indirectly influences regulatory T cell functions.Therefore,TLRs are required in both immuneactivation and immune regulation.Study of TLRs has significantly enhanced our understanding of innate andadaptive immune responses and provides novel therapeutic approaches against infectious and inflammatorydiseases.Cellular & Molecular Immunology.2004;1(4):239-246.     

从频率因素分析振动对小白鼠体内~（125）Ⅰ－碘化钠的分布影响

本文系统地观察了不同频率的全身振动引起小白鼠对１２５Ｉ－碘化钠的吸收与分布作用。用放射免疫方法测定小白鼠体内不同组织中碘化钠的分布密度（ｃｐｍ／ｋｇ）。结果发现，振动能明显促进小白鼠对碘化钠的吸收速度。其中，心脏组织、肝脏组织、血液和肾脏组织中碘化钠的分布密度较对照组明显增多。且分布密度的大小依赖于振动频率的高低。同时，振动还能加快碘化钠在小鼠体内的耗散过程。     

巯甲丙脯酸对实验性冠状动脉痉挛致左室功能不全的作用

犬２１只，经左冠脉内注射麦角新硷诱发冠脉痉挛后随机静滴生理盐水（对照组）或等量盐水溶的巯甲丙脯酸（治疗组），观察１小时。心电图显示治疗组的异常ＳＴ段下降和严重室性心律失常明显少于对照组；冠脉造影显示治疗组痉挛血管支数及狭窄程度均少于和轻于对照组；左室造影和超声心电图显示治疗组的左室收缩末和舒张末容积小于对照组，ＥＦ值或△Ｄ大于对照组，ＡＡ／ＥＡ小于对照组；血流动力学参数表明治疗组左室收缩压，平均肺